1. Field of the Invention
This invention relates to posts or pilings and protective end caps.
2. Prior Art
Wooden posts and pilings deteriorate in use from exposure to weather, bacteria, fungii and insects. A primary cause of this deterioration is the entry of moisture at end surfaces of the post of piling, due to the exposed end grain. Moisture is carried into the post by capillary attraction and may cause the wood to rot or may become frozen and expand to cause cracks and structural defects that shorten the useful life of the post. This deterioration requires the replacement of posts or pilings at considerable expense and is a particular problem in docks and other structures in which posts and pilings are continually subjected to water and weather. While posts and pilings are typically treated chemically, this treatment does not inhibit deterioration to the extent desired.
In the past, various covers or caps for pilings have been suggested or used. These include bituminous material such as tar paper as a cushion on the top of a post, covered with a galvanized metal cap (U.S. Pat. No. 1,637,627), an asphalt covering and a metal cap screwed to the top of the post (U.S. Pat. No. 1,707,397), a steel or copper cover with screws in a flange covering a felt pad over the end of a post, the felt pad serving as a reservoir of preservative (U.S. Pat. No. 1,996,401), a cake of wood preservative on the end of a pole, covered by an elastic cap stretched over the top (U.S. Pat. No. 3,319,328), and a metal pile shoe with wings that fold around periphery of the post are nailed in place (U.S. Pat. No. 3,514,959).
The present state of the art to applicant's knowledge includes the use of fiber glass cloth impregnated with a slow cure resin that is layered upon and formed to the contour of the end of the post or piling. This covering tends to pull away during the cure and leaves voids between the post or piling end and the covering cloth and when unsupported and being somewhat brittle in nature, it tends to crack or be otherwise damaged from impacts. The state of the art also includes the use of a soft metal disk across the top of a piling, hammered into shape about the end and nailed in place around a skirt portion. Typically, the formed disk is not in intimate contact throughout its extent with the surface of the post or piling and therefore tends to be easily puncture. In the case of both such covers, substantial preservative is applied prior to covering the post or piling and the application of preservative and installation of either such cover will require substantial time, reportedly on the order of 45 minutes.
In addition to the above, it is known to set poles in the ground and fill the space between the pole and surrounding ground surfaces with an expanded foam resin (U.S. Pat. Nos. 3,403,520 and 3,564,859) or to encase the tip of a pile in concrete (U.S. Pat. No. 4,006,600).